Re: [PATCH] mm: make __GFP_SKIP_ZERO visible to skip zero operation

[Zhaoyang Huang]

loop alex

On Thu, Aug 31, 2023 at 8:16 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Thu, Aug 31, 2023 at 06:52:52PM +0800, zhaoyang.huang wrote:
> > From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> >
> > There is no explicit gfp flags to let the allocation skip zero
> > operation when CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y. I would like to make
> > __GFP_SKIP_ZERO be visible even if kasan is not configured.
>
> This bypasses a security feature so you're going to have to do a little
> better than "I want it".
Thanks for pointing this out. What I want to do is to give the user a
way to exempt some types of pages from being zeroed, which could help
on performance issues.  Could we have the most safety concern admin
use INIT_ON_FREE while the less concerned use INIT_ON_ALLOC &
__GFP_SKIP_ZERO as a light version method?
>
> > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> > ---
> >  include/linux/gfp_types.h | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >  mode change 100644 => 100755 include/linux/gfp_types.h
>
> What is this garbage?  Header files should not be executable.
sorry for that, will remove